Few cocktails are as timeless as the Old Fashioned. With just whiskey, sugar, bitters, and ice, it’s a simple drink—but the choice of bitters can dramatically change its character. If you’re wondering which bitters to use in an Old Fashioned, the answer depends on the flavor profile you want to create.

If you’ve ever sipped a perfectly balanced Old Fashioned or a crisp, aromatic Martini and wondered what gave it that extra edge, it was probably the bitters. Though used in small amounts, bitters are the backbone of classic and modern cocktails alike, adding depth, complexity, and balance.